Learn about sustainable development at Oct. 24 seminar

What is there not to like about a subdivision that is landscaped beautifully, costs less to build than a conventional subdivision and has less of a negative environmental impact than standard construction?

By Anne Mazar/DAILY NEWS CORRESPONDENT

Wicked Local

By Anne Mazar/DAILY NEWS CORRESPONDENT

Posted Oct. 14, 2013 at 12:01 AM
Updated Oct 14, 2013 at 2:19 PM

By Anne Mazar/DAILY NEWS CORRESPONDENT

Posted Oct. 14, 2013 at 12:01 AM
Updated Oct 14, 2013 at 2:19 PM

» Social News

What is there not to like about a subdivision that is landscaped beautifully, costs less to build than a conventional subdivision and has less of a negative environmental impact than standard construction?

Low Impact Development , LID, uses sustainable techniques to design commercial and residential developments that are cost effective for developers and residents, while saving cities and towns money through reduced maintenance costs. Unfortunately, many municipalities inadvertently have antiquated zoning bylaws and subdivision regulations that do not allow LID.

Scott Horsley, principal at the Horsley Witten Group headquartered in Sandwich, Mass., says that LID is basically, "… replacing concrete with dirt." With 25 years of experience, Horsley has used a holistic design approach that considers natural resource protection, lessening energy consumption, working with the natural hydrology, minimizing land clearing, clustering buildings and reducing impervious surfaces. Horsley says, "Ideally, towns should consider provisions to promote LID, not discourage it."

However, many cities and towns require 35-foot road widths in subdivisions, curbing, catch basins and other regulations that hamper environment-friendly development.

LID is designed to work with nature. Land is protected for scenic open space and aquifer protection. Natural hydrology is utilized so rainwater is absorbed into the ground to prevent flooding. Natural filtration through the soil prevents water pollution. Buildings can be sited to accommodate solar PV systems. It takes thinking "outside of the box" of conventional design.

E. Heidi Ricci, a senior policy analyst at Mass Audubon, explains, "Among the many benefits, LID does not create mosquito breeding habitat, unlike conventional catch basins and wet detention areas." Traditional building techniques funnel rainwater runoff over hard surfaces, by way of road curbing and underground piping, to a central location, such as a catch basin and a wet detention basin, which creates unnatural stagnant water. Instead, Ricci says, "LID features, such as rain gardens and grassy swales, filter runoff and let it percolate into the ground." The landscaped swales (shallow depression in the land) are located by rooftop, parking lots and any hard surface where rainwater runs off. The water flows into these small valleys that are ideally planted with native flood tolerant flowers, shrubs and trees to absorb the water.

When rainwater flows over unnatural hard surfaces, it picks up roadside oil from cars, lawn chemicals and other pollutants before it washes into storm drains, eventually dumping untreated polluted water into our streams, lakes and oceans. Studies by the U.S. Environmental Protection Agency have shown that a significant amount of the pollutants in our waterways is carried off from our yards, rooftops and driveways.

Also, during heavy downpours, channeling rainwater away from where it fell and directing all the water runoff from a development to one central location produces large quantities of water, which can blast through streams and rivers causing erosion, destroying wildlife habitat and sometimes dismantling road culverts or bridges. LID makes homes, commercial developments and municipal infrastructure more resilient to extreme storm events.

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Additionally, channeling rainwater away can also deplete the local aquifer. Rainwater should replenish local groundwater supplies. Another advantage of keeping the rainwater on site, in bioretention areas or rain barrels, is that the water can be used to irrigate lawns and gardens. Conversely, conventional development directs the water away and, adding insult to injury, requires further draining of the public water supply or well for irrigation.

LID has a financial bonus, since it requires less upfront cost using less roads, pavement and storm drainage infrastructure. Municipalities save taxpayer dollars on annual road and stormwater infrastructure maintenance. Public water systems have fewer sewer overflows and the related costs, because less water flows into the systems.

Many towns work from outdated storm and flood data. The precipitation data many Massachusetts towns are using to design new infrastructure is from the 1930s to 1960s. Storm intensity has greatly increased in the last 50 years. Municipalities should use more accurate data to build durable culverts, bridges and roads that will stay intact for extreme weather events. Cornell University's Northeast Regional Climate Center has accurate current precipitation data. Visit www.nrcc.cornell.edu/page_nowdata.html for more information.

Another option is using porous asphalt pavement, which allows water to drain straight through the asphalt recharging aquifers, preventing flooding and reducing the need for stormwater infrastructure (pipes, catch-basins, curbs etc). It also reduces or eliminates the need for road salt. It costs between 20 percent to 25 percent more initially, but can save costs in the long run. The University of New Hampshire's Stormwater Center website has details on the porous asphalt and other useful information. Visit www.unh.edu/unhsc.

Bridgewater State University will host a free LID workshop open to all on Oct. 24, from 4:30-6:30 p.m. Presenters will include Scott Horsley, principal, Horsley Witten Group; E. Heidi Ricci, senior policy analyst, Mass Audubon, and Cathy Bozek, aquatic ecologist, the Nature Conservancy. For more information visit www.massaudubon.org/catalog/listing.php?program_code=CO28941